Summary

Thyroid hormones thyroxine (T4) and triiodothyronine (T3) are produced, stored, and secreted by the thyroid gland. These hormones, particularly T3, play a major role in multiple biologic and metabolic processes. They act by binding to thyroid receptors that are distributed in almost every organ. Typically, this process regulates gene transcription and the subsequent production of various proteins that are involved in development, growth, and cellular metabolism.
[1]Kronenberg HM, Melmed S, Polonsky KS, et al, eds. Williams textbook of endocrinology. 12th ed. Philadelphia, PA: Saunders/Elsevier; 2011.
Thyroid function tests (TFTs) are the most commonly used endocrine test.
American Thyroid Association: thyroid function tests